1. Field of the Invention
The present invention pertains to pivot joints. The invention more particularly concerns an improved pivot joint for use with floor machines such as floor polishers.
2. Discussion of the Background
An existing floor machine such as a floor polisher or vacuum may include a base comprising a motor housing, bumpers for avoiding scuffs on the base, a cavity for housing the components of the floor machine which are in operative contact with the floor, the operative components themselves (such as brushes), and tires or rollers, and the floor machine may further include a yoke having a handle for the user to grasp. The base and yoke of such a floor machine are, ideally, pivotally attached to allow the user to raise or lower the handle as it pivots about the base.
The pivotal attachment of the base and yoke of such a floor machine is currently achieved using cylindrical shafts inserted into bores. This type of pivotal attachment can be relatively simple with few moving parts compared to other existing designs, and thus may be less expensive to manufacture at relaxed tolerances for error, but suffers from a number of inherent pitfalls. Among them is the fact that use of this design requires a manufacturer to balance the need for a flush fit between such a cylindrical shaft and bore with the need to reduce manufacturing costs by relaxing machining tolerances such as those relating to shaft and bore shape and dimensions. The less perfectly a manufacturer machines the shaft and bore, the more jerky a user will find the floor machine's operation, but the cheaper the manufacturing process. For example, if the shaft is undersized even to a modest extent in relation to the bore it occupies, that disparity will be magnified along the length of the yoke such that a user will experience delayed resistance when trying to manipulate the handle. Because of this, the user may experience jerky and unsatisfactory operation of the floor machine.
Further, many manufacturers will attempt to remedy jerky operation resulting from such pivotal attachments by inserting plastic liners or similar materials into the areas where the shafts and bores are mated. While this may temporarily alleviate jerky operation of the floor machine, such quick fixes are an added cost for parts which are quickly worn down through usage, resulting in additional harm to users' confidence in the durability of their floor machines.
Finally, the shafts which form these pivotal attachments do not offer a user the option of easily adjusting a yoke relative to a base.
There is thus a need for an improved pivot joint providing for more beneficial combinations of adjustability, management of manufacturing costs, and smoothness of operation.